JP2022111611A - Liquid jet device - Google Patents

Abstract

To enable a distance by which droplets are formed to be shortened even during high-speed jetting.SOLUTION: A liquid jet device 1 comprises: a passage 3 through which liquid 5 is fed to a nozzle 7 that jets the liquid 5; a pressurizing part 9 that presses out the liquid 5 into the passage 3; a piezoelectric element 11, provided adjacent to the passage 3 at an upstream of the nozzle 7, which applies vibrations to the liquid 5; and a vibration plate 15, provided between a first surface 13 of the piezoelectric element 11 and the passage 3, which segregates the passage 3. Further, the device comprises a regulating part 21, arranged on a second surface 17 at the opposite side of the first surface 13 of the piezoelectric element 11, which regulates thickness vibrations toward a direction 19 opposite to a direction of the first surface 13 of the piezoelectric element 11.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a liquid injection apparatus such as a dental treatment apparatus that injects a liquid at high pressure toward an object such as a tooth and causes it to collide with the object to clean, peel, scrape, or the like the object.

Patent Documents 1 and 2 disclose one example of this type of liquid ejecting apparatus. In this document, a water jet nozzle and an ultrasonic water jet nozzle for cutting or cleaning an object by making droplets of a continuous flow of high-pressure water to be jetted to increase the impact force and making the droplets collide with the object are disclosed. A jet device is disclosed.

JP-A-2-145296 Special Table 2007-523751

When the ultrasonic water device is applied to dental treatment such as dental caries removal and tartar removal, the liquid jet speed is sufficiently high compared to the normal use, and the droplet forming distance is close to the jet nozzle. There is a need to. However, in the water jet device described in Patent Document 1, the surface of the piezoelectric element opposite to the flow path is free, so when the piezoelectric element is driven at a high frequency necessary for forming droplets during high-speed jetting. However, there is a problem that it is difficult to shorten the droplet forming distance because the vibration cannot be sufficiently transmitted from the piezoelectric element to the liquid.
Moreover, since the invention described in Patent Document 2 vibrates a long probe portion, it is difficult to increase the frequency due to its mass.

In order to solve the above-described problems, a liquid ejecting apparatus according to the present invention provides a flow path for sending the liquid to a nozzle for ejecting the liquid, a pressurizing section for pushing the liquid into the flow path, and an upstream of the nozzle. a piezoelectric element provided adjacent to a flow path to apply vibration to the liquid; a vibration plate provided between a first surface of the piezoelectric element and the flow path to isolate the flow path; and the piezoelectric element. and a regulating portion disposed on a second surface opposite to the first surface of the piezoelectric element for regulating thickness vibration of the piezoelectric element in a direction opposite to the first surface.

1 is an overall schematic configuration diagram of a liquid ejecting apparatus according to Embodiment 1 of the present invention; FIG. FIG. 2 is a schematic cross-sectional view of a main part of the same Embodiment 1; FIG. 4 is a schematic cross-sectional view of a main part for explaining the effects of the first embodiment; FIG. 2 is a schematic cross-sectional view of a main part of a liquid ejecting apparatus according to Embodiment 2 of the present invention; FIG. 7 is a schematic cross-sectional view of a main part of a liquid ejecting apparatus according to Embodiment 3 of the present invention; FIG. 11 is a schematic cross-sectional view of a main part for explaining the effects of the third embodiment;

The present invention will first be described schematically below.
In order to solve the above-described problems, a first aspect of a liquid ejecting apparatus according to the present invention includes a channel for sending the liquid to a nozzle for ejecting the liquid, a pressurizing section for pushing the liquid into the channel, and the a piezoelectric element provided upstream of the nozzle and adjacent to the flow path to apply vibration to the liquid; and a vibration plate provided between a first surface of the piezoelectric element and the flow path to isolate the flow path. and a regulating portion disposed on a second surface opposite to the first surface of the piezoelectric element for regulating thickness vibration of the piezoelectric element in a direction opposite to the first surface. do.

According to this aspect, since the thickness vibration of the piezoelectric element in the direction opposite to the first surface is regulated by the regulating portion, even a minute displacement during high-frequency driving can be efficiently applied to the diaphragm. can tell That is, the thickness vibration in the direction from the first surface of the piezoelectric element toward the diaphragm can be efficiently transmitted to the diaphragm. As a result, it is possible to efficiently vibrate the liquid flowing through the flow path upstream of the nozzle, and it is possible to shorten the droplet formation distance even during high-speed ejection.

A liquid ejecting apparatus according to a second aspect of the present invention is characterized in that, in the first aspect, the driving frequency of the piezoelectric element is 100 kHz or higher.

According to this aspect, since the driving frequency of the piezoelectric element is 100 kHz or higher, the droplet forming distance can be effectively shortened compared to the distance at which the droplet is naturally formed by the surface tension.

A liquid ejecting apparatus according to a third aspect of the present invention is characterized in that, in the first aspect or the second aspect, the restricting portion is arranged so as to cover the entire second surface of the piezoelectric element. .

According to this aspect, since the restricting portion is arranged so as to cover the entire second surface of the piezoelectric element, the thickness vibration in the direction from the first surface of the piezoelectric element toward the vibration plate is suppressed. can be transmitted to the plate more efficiently.

A liquid ejecting apparatus according to a fourth aspect of the present invention is characterized in that, in any one of the first to third aspects, the thickness of the vibration plate is thinner than the thickness of the piezoelectric element.

According to this aspect, since the thickness of the diaphragm is thinner than the thickness of the piezoelectric element, the diaphragm can be easily deformed by the vibration of the piezoelectric element. can be efficiently communicated to It is desirable that the thickness of the diaphragm is 1/2 or less of the thickness of the piezoelectric element.

A liquid ejecting apparatus according to a fifth aspect of the present invention is characterized in that, in the fourth aspect, the diaphragm has a thickness of 1 mm or less.

According to this aspect, since the thickness of the diaphragm is 1 mm or less, it is possible to provide a structure in which the diaphragm is more easily deformed by the vibration of the piezoelectric element.

A liquid ejecting apparatus according to a sixth aspect of the present invention is characterized in that, in the fourth aspect or the fifth aspect, the thickness of the piezoelectric element is 1 mm or less.

According to this aspect, since the thickness of the piezoelectric element is 1 mm or less, it is possible to drive at a high frequency even when one side of the piezoelectric element is fixed by the restricting portion.

In a liquid ejecting apparatus according to a seventh aspect of the present invention, in any one of the first aspect to the sixth aspect, the length of at least a portion of the piezoelectric element in a direction perpendicular to the thickness direction is: The thickness is five times or more the thickness of the piezoelectric element.

According to this aspect, the length of at least part of the piezoelectric element in the direction orthogonal to the thickness direction is five times or more the thickness of the piezoelectric element. As a result, the shape of the piezoelectric element is thin and wide, and a large drive area for the diaphragm can be ensured. Furthermore, the vibration mode of the piezoelectric element is limited to vibration in the thickness direction, and the vibration plate can be vibrated at a stable high frequency.

According to an eighth aspect of the present invention, in any one of the first to seventh aspects, a filling layer is provided between the restricting portion and the second surface of the piezoelectric element. characterized by the presence of
Here, the "filling layer" means a layer that is in close contact with both the regulating portion and the second surface of the piezoelectric element.

According to this aspect, there is a filling layer between the restricting portion and the second surface of the piezoelectric element. That is, since the filling layer is present in close contact with both the regulating portion and the second surface of the piezoelectric element, thickness vibration in the direction opposite to the first surface of the piezoelectric element by the regulating portion is effectively controlled. can be regulated.

A liquid ejecting apparatus according to a ninth aspect of the present invention is the liquid ejecting apparatus according to the eighth aspect, wherein the restricting portion is made of a metal material or a ceramic material, and the filling layer is made of a resin material having a smaller bending rigidity than the material of the restricting portion. characterized by being formed

According to this aspect, since the filling layer is formed of a resin material having a smaller flexural rigidity than the material of the restricting portion, only compressive stress is applied to the filling layer made of the resin material. The thickness vibration of the piezoelectric element in the direction opposite to the first surface can be effectively regulated by the regulating portion.

A liquid ejecting apparatus according to a tenth aspect of the present invention is characterized in that, in the eighth aspect or the ninth aspect, the regulating portion has a through-hole extending from the back surface on the filling layer side to the front surface.

According to this aspect, the restricting portion has a through-hole extending from the back surface on the filling layer side to the front surface. Thus, by pressing the restricting portion after pouring the material of the filling layer in a molten state into the filling place, the excess material can be discharged from the through hole. Therefore, it is possible to easily install a filling layer with good adhesion.

A liquid ejecting apparatus according to an eleventh aspect of the present invention is, in any one of the first to tenth aspects, provided with a control section for controlling operations of the pressurizing section and the piezoelectric element, The liquid ejected from the nozzle under the control of the control unit has a distance of 10 mm or less until it splits into droplets from a continuous flow.

According to this aspect, since the droplet forming distance is 10 mm or less, it is possible to realize a liquid ejecting apparatus that is used in a narrow space such as the oral cavity in dental treatment.

[Embodiment 1]
A liquid ejecting apparatus according to Embodiment 1 of the present invention will be described in detail below with reference to FIGS. 1 to 3. FIG. Here, the liquid ejecting apparatus 1 is described as a dental treatment apparatus.
In the following description, the three mutually orthogonal axes are the X-axis, the Y-axis, and the Z-axis, respectively, as shown in each drawing. The Z-axis direction corresponds to the vertical direction. The X-axis direction and the Y-axis direction correspond to the horizontal direction.

As shown in FIG. 1, the liquid ejecting apparatus 1 according to the present embodiment includes a channel 3 that sends the liquid 5 to a nozzle 7 that ejects the liquid 5, and a pressure unit 9 that pushes the liquid 5 into the channel 3. a piezoelectric element 11 provided upstream of the nozzle 7 and adjacent to the flow path 3 to apply vibration to the liquid 5; and an isolating diaphragm 15 .
In addition, a regulating portion that is arranged on the second surface 17 of the piezoelectric element 11 opposite to the first surface 13 and regulates thickness vibration in the direction 19 (+Z-axis direction) opposite to the first surface 13 of the piezoelectric element 11. 21. Of course, the direction of thickness vibration is not limited to the Z-axis direction. That is, the piezoelectric element 11 may be arranged on a plane other than the XY plane.
Further, a control unit 23 for controlling the operation of the pressure unit 9 and the piezoelectric element 11 is provided.

Specifically, the liquid ejecting apparatus 1 according to the present embodiment includes a head portion 2 having a nozzle 7 , a tank 4 that stores the liquid 5 to be ejected, and a flow path 3 that connects the pressurizing portion 9 and the tank 4 . and a liquid-sending tube 8 that connects the liquid-sending pump 9 and the head portion 2 and that also forms the flow path 3 . The head section 2 and the control section 23 are connected by a drive signal line 10 . Also, the liquid-sending pump 9 and the controller 23 are connected by a control signal line 12 .

As shown in FIG. 2, the head section 2 has a liquid chamber 16 . The liquid chamber 16 is connected to the nozzle 7 , and the liquid 5 guided into the liquid chamber 16 is jetted from the jet port 22 of the nozzle 7 as a high-speed jet fluid b ( FIG. 1 ). This nozzle 7 has a conical enclosure 34 at the tip of the injection port 22 . The liquid chamber 16 is formed by being surrounded by a channel member 18 in which the nozzles 7 are formed, a vibration plate 15 which is a diaphragm, and an intermediate member 20 positioned between the vibration plate 15 and the channel member 18. there is The liquid 5 in the liquid chamber 16 is jetted from the nozzle 7 located in the direction (−Z-axis direction) in which the vibrating plate 15 vibrates.
The head portion 2 also has a grip portion 14 . The user grasps the grasping portion 14 and moves the head portion 2 relative to the liquid ejection target (not shown).

Each component of the liquid ejecting apparatus will be described in detail below.
<Flow path, pressurizing part>
As shown in FIG. 2 , in this embodiment, the flow path 3 is also formed inside the grip portion 14 , and the liquid-sending tube 8 is connected to the flow path 3 inside the grip portion 14 . The channel 3 in the grip portion 14 is connected to the liquid chamber 16 via an introduction channel 24 formed in the channel member 18 . The introduction channel 24 is formed to have a smaller diameter than the channel 3 in the grip portion 14 .
In this embodiment, the flow path 3 is composed of the inside of the liquid suction tube 6, the inside of the liquid feeding tube 8, the inside of the grip portion 14, the introduction flow path 24 of the flow path member 18, and the liquid chamber 16 as a whole. there is
Although the channel member 18 and the gripping portion 14 are integrally formed here, the present invention is not limited to this, and the channel member 18 and the gripping portion 14 may be made separately and assembled together. .
In this embodiment, the pressurizing section 9 is configured by a liquid transfer pump 9 (using the same reference numerals as the "pressurizing section").

<Diaphragm>
As shown in FIG. 2, diaphragm 15 is made of a metal thin film. The vibrating plate 15 is provided between a first surface 13 of the piezoelectric element 11 and a portion of the flow path 3 forming the liquid chamber 16 to isolate the liquid chamber 16 . That is, the vibration plate 15 is arranged at a position on the inner surface of the liquid chamber 16 facing the nozzle 7 provided in the flow path member 18 . The shape of the diaphragm 15 here is disk-shaped in plan view.
Specifically, a ring-shaped intermediate member 20 is arranged at a position where the nozzle 7 of the channel member 18 is positioned inside the liquid chamber 16, and the peripheral edge portion of the diaphragm 15 is adhesively fixed to the intermediate member 20. there is Thus, as described above, the liquid chamber 16 is defined by the vibrating plate 15 , the intermediate member 20 , and the portion of the channel member 18 having the nozzles 7 .

In this embodiment, the thickness of the vibration plate 15, that is, the thickness of the metal thin film is thinner than the thickness of the piezoelectric element 11, which will be described later. Thereby, the vibration plate 15 has a structure that is easily deformed by the vibration of the piezoelectric element 11 .
Specifically, the thickness of the vibration plate 15 is desirably 1/2 or less of the thickness of the piezoelectric element 11 . Here, the thickness of the diaphragm 15 is 0.1 mm, which is 1 mm or less.

<Piezoelectric element>
The piezoelectric element 11 is provided adjacent to the flow path 3 upstream of the nozzle 7 and configured to apply vibrations to the liquid 5 . In this embodiment, the drive frequency of the piezoelectric element 11 is configured to be 100 kHz or higher.
The piezoelectric element 11 is fixed to the surface of the vibration plate 15 opposite to the liquid chamber 16 . That is, the first surface 13 of the piezoelectric element 11 contacts the diaphragm 15 . Here, the shape of the piezoelectric element 11 is disk-shaped in plan view, like the diaphragm 15 .
In this embodiment, the piezoelectric element 11 is a single-plate ceramic piezoelectric element made of lead zirconate titanate (PZT), which is bonded and fixed to the vibration plate 15 with a conductive adhesive. This single-plate piezoelectric element can be miniaturized and is a suitable material for obtaining thickness-direction displacement at high frequencies. The piezoelectric element 11 is not limited to PZT, and other materials such as BaTiO3, PbTiO3, and ceramic-based piezoelectric elements may be used.

As shown in FIG. 2, one of the driving signal lines 10 is conductively fixed to the diaphragm 15 and the other is directly conductively fixed to the electrode of the piezoelectric element 11 . In FIG. 2, reference numerals 26 and 28 denote holes formed in the regulation portion 21, which will be described later, through which the respective drive signal lines 10 are passed. The holes 26 and 28 for passing the respective drive signal lines 10 may be provided in the intermediate member 20 .
The size of the piezoelectric element 11 with respect to the diaphragm 15 is, as shown in FIG. .

In this embodiment, the thickness of the piezoelectric element 11 is 1 mm or less. Specifically, the thickness of the piezoelectric element 11 is 1 mm, and the thickness of the vibration plate 15 satisfies the relationship that it is desirable that the thickness of the piezoelectric element 11 is 1/2 or less.
At least a part of the piezoelectric element 11 has a length in the in-plane direction perpendicular to the thickness direction, which is five times or more the thickness of the piezoelectric element 11 . Here, since the piezoelectric element 11 is disc-shaped, the diameter of the circle is five times or more the thickness. When the piezoelectric element 11 is rectangular, the length of the long side is formed to be at least five times the thickness.

<Regulatory Department>
As described above, the restricting portion 21 is arranged on the second surface 17 opposite to the first surface 13 of the piezoelectric element 11, and extends in the opposite direction 19 (+Z-axis direction) to the first surface 13 of the piezoelectric element 11. Regulate thickness vibration. In this embodiment, the restricting portion 21 is made of a metal material having corrosion resistance and high rigidity, such as stainless steel SUS316L or titanium, and is formed into a disc shape having an outer diameter approximately equal to the outer diameter of the intermediate member 20. It is Note that the restricting portion 21 is not limited to a metal material, and a ceramic material can also be used. Examples of ceramic materials include zirconia and silicon nitride.
Further, the restricting portion 21 is arranged on the second surface 17 of the piezoelectric element 11 so as to cover the entire surface thereof as shown in FIG. 2, and is adhered and fixed with an adhesive. The restricting portion 21, the intermediate member 20, and the diaphragm 15 are further firmly fixed by screws (not shown).

<Control part>
The control unit 23 controls the operations of the pressure unit 9 and the piezoelectric element 11 as described above.
In this embodiment, the control unit 23 controls the piezoelectric element so that the liquid 5 ejected from the nozzle 7 is separated from the continuous flow 3a into droplets 3b (FIG. 1) by a distance of 10 mm or less. 11 is controlled. Specifically, the pressure applied by the pressure unit 9 and the driving frequency of the piezoelectric element 11 are set so that the droplet formation distance is set to 10 mm or less, and controlled so that it can be used for dental treatment.
For use in dental treatment, the thickness (Z-axis direction) of the head 2 is preferably 20 mm or less.

<Description of the action of the first embodiment>
Next, based on FIG. 3, the operation of the dental treatment apparatus, which is the liquid ejecting apparatus 1 of Embodiment 1, will be described in comparison with the conventional structure.
The user holds the grip part 14 in his/her hand and brings the injection port 22 of the nozzle 7 closer to the tooth, which is the object to be injected. Then, a trigger (not shown) is operated to send a control signal through the controller 23 to drive the liquid feed pump 9 . As a result, the liquid 5 in the liquid tank 4 is sent to the liquid chamber 16 in a pressurized state through the flow path 3 . Further, the piezoelectric element 11 is operated by the drive signal from the control unit 23, and vibrations with a drive frequency of 100 kHz or more are applied to the diaphragm 15. FIG. As a result, the liquid 5 in the liquid chamber 16 is jetted from the jetting port 22 of the nozzle 7 toward the teeth as jetting fluid b with a droplet forming distance of 10 mm or less.
At that time, as shown in (D) of FIGS. 2 and 3 , the presence of the restricting portion 21 reduces the thickness of the piezoelectric element 11 in the opposite direction 19 (+Z-axis direction) to the first surface 13 of the piezoelectric element 11 . Vibration is regulated. That is, the thickness vibration from the first surface 13 of the piezoelectric element 11 in the direction f toward the diaphragm 15 is efficiently transmitted to the diaphragm 15 .

When the liquid 7 jetted from the nozzle 7 collides with the object to be sprayed, the force received by the object from the liquid with which the object collides is, in the state of the continuous flow 3a, the velocity of the colliding liquid V, the density of the liquid is given as the stagnation point pressure of ^1/2 x ρ x V2.
On the other hand, when it becomes a droplet 3b, the impact pressure is given by ρ×C×V, where C is the speed of sound of the colliding liquid.
For example, since the speed of sound of water is about 1500 m/s, when the jet speed of the liquid 5 is 100 m/s, the force applied to the object is 30 times greater in the state of droplets 3b than in the state of continuous flow 3a. Therefore, crushing and excision of the object can be performed very effectively even with the same flow rate.

On the other hand, when there is no restricting portion 21, as shown in FIGS. It cannot be efficiently transmitted to the plate 15.
As shown in FIG. 3A, when the liquid 5 flows into the liquid chamber 16 as a high-pressure fluid without the restricting portion 21, both the vibration plate 15 and the piezoelectric element 11 are thin. This is because the diaphragm 15 warps due to the high pressure, as shown in FIG. 3B. Furthermore, this warping may cause cracks d in the piezoelectric element 11 or separation between the vibration plate 15 and the piezoelectric element 11 .
For example, when water is jetted at 5 ml/min from the nozzle 7 whose diameter of the jet port 22 is 50 μm, the internal pressure of the liquid chamber 16 is close to 2.4 MPa. Assuming that the diaphragm 15 has a size of about 2.5 cm ² , the force applied to the diaphragm 15 is about 60 kgf.
3C, when the piezoelectric element 11 is deformed in the thickness direction by voltage application, the side where the vibration plate 15 having a large resistance exists It is easier to deform in the direction of arrow e, which is open. Therefore, thickness vibration from the piezoelectric element 11 cannot be efficiently transmitted to the diaphragm 15 .

<Description of the effects of the first embodiment>
(1) According to the present embodiment, since the thickness vibration in the direction 19 opposite to the first surface 13 of the piezoelectric element 11 is restricted by the restricting portion 21, even a minute displacement during high-frequency driving does not affect the diaphragm 15. The displacement can be efficiently transmitted. That is, the thickness vibration in the direction from the first surface 13 of the piezoelectric element 11 toward the diaphragm 15 can be efficiently transmitted to the diaphragm 15 . As a result, the liquid 5 flowing through the flow path 3 upstream of the nozzle 7 can be efficiently vibrated, and the droplet formation distance can be shortened even during high-speed ejection.

(2) In addition, according to the present embodiment, since the drive frequency of the piezoelectric element 11 is 100 kHz or more, the droplet formation distance can be effectively shortened from the distance at which droplets are naturally formed by surface tension. .
(3) In addition, according to the present embodiment, since the restricting portion 21 is arranged so as to cover the entire second surface 17 of the piezoelectric element 11, the direction from the first surface 13 of the piezoelectric element 11 toward the diaphragm 15 The thickness vibration to f can be transmitted to the diaphragm 15 more efficiently.
(4) According to the present embodiment, since the thickness of the diaphragm 15 is thinner than the thickness of the piezoelectric element 11, the diaphragm 15 can be easily deformed by the vibration of the piezoelectric element 11. It becomes possible to efficiently transmit the thickness vibration to the diaphragm 15 .

(5) Further, according to the present embodiment, since the thickness of the diaphragm 15 is 1 mm or less, it is possible to provide a structure in which the diaphragm 15 is more easily deformed by the vibration of the piezoelectric element 11 .
(6) Further, according to the present embodiment, since the thickness of the piezoelectric element 11 is 1 mm or less, it is possible to drive at a high frequency even when one side of the piezoelectric element 11 is fixed by the restricting portion 21 . .
(7) According to the present embodiment, the length of at least a portion of the piezoelectric element 11 in the direction perpendicular to the thickness direction is 5 times or more and 10 times the thickness of the piezoelectric element 11 . As a result, the shape of the piezoelectric element 11 is thin and wide, and a large drive area for the diaphragm 15 can be ensured. Furthermore, the vibration mode of the piezoelectric element 11 is limited to vibration in the thickness direction, and the vibration plate 15 can be vibrated at a stable high frequency.

[Embodiment 2]
Next, a liquid injection device 1 according to Embodiment 2 of the present invention will be described with reference to FIG.
In the liquid ejecting apparatus 1 of this embodiment, the restricting portion 21 is made of a resin material. The flow path member 18 is formed with a concave portion 30 into which the fluid can flow into a portion of the vibration plate 15 and the piezoelectric element 11 opposite to the liquid chamber 16 . The regulating portion 21 is formed by pouring a molten resin into the recess 30 and hardening it.
As the resin material, it is possible to use epoxy resin, UV curable resin, thermoplastic resin, etc., which can maintain fluidity before curing.
Here, when the regulating portion 21 is made of the above resin material, its thickness must be set to a size that can withstand the applied high pressure. The thickness can be easily determined by performing a pressure resistance test against the pressure applied to each material used.

In this embodiment, the resin material is poured into the concave portion 30 while the drive signal line 10 is conductively fixed to the vibration plate 15 and the electrodes of the piezoelectric element 11 . Therefore, formation of the holes 26 and 28 as in the first embodiment is not required.
Moreover, the flow path 3 is not provided in the holding portion 14, and the drive signal line 10 is passed through. The channel member 18 has a tube connection portion 32 . A liquid-sending tube 8 is connected to the tube connection portion 32 . In this embodiment, the nozzle 7 is composed of a small diameter portion 36 and a large diameter portion 38 having different diameters.
Since other configurations are the same as those of the first embodiment, the same reference numerals are given to the same parts, and the description thereof will be omitted. In addition, explanations of the same functions and effects as those of the first embodiment will be omitted.

<Description of the effects of the second embodiment>
According to this embodiment, since the restricting portion 21 is made of a resin material, excessive stress is not applied to the piezoelectric element 11 even when the restricting portion 21 is in close contact with the piezoelectric element 11 . Accordingly, the restricting portion 21 can be easily provided without the need for precise height control.

[Embodiment 3]
Next, a liquid injection device 1 according to Embodiment 3 of the present invention will be described with reference to FIGS. 5 and 6. FIG.
In the liquid ejecting apparatus 1 of this embodiment, the filling layer 25 is provided between the restricting portion 21 and the second surface 17 of the piezoelectric element 11 . Here, the filling layer 25 means a layer in close contact with both the restricting portion 21 and the second surface 17 of the piezoelectric element 11 . The filling layer 25 is made of a resin material.
A concave portion 30 is formed in the channel member 18 as in the second embodiment. The filling layer 25 is formed by pouring molten resin into the recess 30 and curing it.
The restricting portion 21 is made of a metal material or a ceramic material, and the filling layer 25 is made of a resin material having a lower bending rigidity than the material of the restricting portion 21 . As specific examples of the metal material, ceramic material, and resin material, materials similar to those mentioned in the first and second embodiments can be used.

Further, in this embodiment, the restricting portion 21 has two through-holes 31 extending from the rear surface 27 on the side of the filling layer 25 to the front surface 29 .
Although the through hole 31 is shown as a straight hole in FIG. 5, it is not limited to this, and may be a curved hole. The number of through-holes 31 is not limited to two, and may be one or three or more.

Next, the assembly method will be explained. After pouring the resin material which is the material of the filling layer 25 in a molten state into the concave portion 30 which is the filling place, the restricting portion 21 is pressed from above to bring it into the state shown in FIG. As a result, excess resin material flows out from the through holes 31, and the melted resin material is cured while maintaining this state.
After that, the restricting portion 21 is firmly fixed to the flow path member 18 by welding, screws, or the like. As a result, the regulating portion 21 is fixed to the flow path member 18 in such a manner as to back up the filling layer 25 of the resin material. The layer 25 does not flex due to the high pressure in the liquid chamber 16 and is able to withstand the high pressure.
Since other configurations are the same as those of the second embodiment, the same reference numerals are given to the same parts, and the description thereof will be omitted. In addition, explanations of the same functions and effects as those of the second embodiment will be omitted.

<Description of Effects of Embodiment 3>
(1) According to this embodiment, the filling layer 25 exists between the restricting portion 21 and the second surface 17 of the piezoelectric element 11 . That is, the filling layer 25 is present in close contact with both the restricting portion 21 and the second surface 17 of the piezoelectric element 11 . Thereby, thickness vibration in the direction 19 opposite to the first surface 13 of the piezoelectric element 21 by the restricting portion 21 can be effectively restricted.
6B, the thickness vibration in the direction 19 opposite to the first surface 13 of the piezoelectric element 21 is effectively regulated by the regulating portion 21, and the vibration from the first surface 13 of the piezoelectric element 11 to the vibration plate 15 is suppressed. It shows that the thickness vibration in the direction f toward the diaphragm 15 can be transmitted to the diaphragm 15 more efficiently.
FIG. 6A shows a case where the restricting portion 21 is made of a resin material and the thickness thereof is not a necessary size. That is, since the resin material has low flexural rigidity, it is not possible to suppress the bending of the vibration plate 15 and the piezoelectric element 11 when a high pressure is applied, and the piezoelectric element 11 may crack d.

(2) Further, according to the present embodiment, the restricting portion 21 is made of a metal material or a ceramic material having high bending rigidity, and the filling layer 25 is made of a resin material having a lower bending rigidity than the material of the restricting portion 21 . That is, the filling layer 25 has to bear only the compressive stress due to the high flexural rigidity of the regulating portion 21 . can be effectively regulated.

(3) Further, according to the present embodiment, the restricting portion 21 has the through hole 31 extending from the rear surface 27 on the side of the filling layer 25 to the front surface 29 . As a result, excess material can flow out from the through hole 31 by pressing the restricting portion 21 after the molten material of the filling layer 25 is poured into the recess 30 , which is the filling location. Therefore, it is possible to easily install the filling layer 25 with good adhesion.

[Other embodiments]
Although the liquid ejecting apparatus 1 according to the embodiment of the present invention is basically configured as described above, the partial configuration may be changed or omitted without departing from the gist of the present invention. It is of course possible to do
(1) In the description of the above embodiment, the liquid ejection device 1 is described as a dental treatment device, but it is of course not limited to a dental treatment device. The liquid jetting apparatus 1 jets the liquid 5 from the nozzle 7, and the liquid 5 is jetted from the nozzle 7, and the droplets of the continuous flow collide with the work object with a large impact force. It can be applied to a device for resection, incision, crushing, and the like.
(2) The filling layer 25 in the structure of Embodiment 3 is filled by first creating a space by surrounding the recess 30 with the restricting portion 21, and then sucking and injecting molten resin after the space is evacuated. A layer 25 may be arranged. By this evacuation, the filling layer 25 with almost no gap can be realized.

1 liquid ejecting device, 2 head section, 3 flow path, 4 tank, 5 liquid,
6 liquid suction tube, 7 nozzle, 8 liquid transfer tube, 9 pressure unit (liquid transfer pump),
10 drive signal line, 11 piezoelectric element, 12 control signal line, 13 first surface,
14 gripping portion 15 diaphragm 16 liquid chamber 17 second surface 18 flow path member
19 reverse direction, 20 intermediate member, 21 regulation part, 22 injection port, 23 control part,
24 introduction channel, 25 filling layer, 26 hole, 27 back surface, 28 hole, 29 front surface,
30 recess, 31 through hole, 32 tube connection, 34 conical enclosure,
36 small diameter portion, 38 large diameter portion, b injection fluid, 3a continuous flow, 3b droplet

Claims (11)

a channel for sending the liquid to a nozzle for injecting the liquid;
a pressurizing unit that pushes the liquid into the channel;
a piezoelectric element provided adjacent to the flow path upstream of the nozzle and applying vibration to the liquid;
a vibration plate provided between the first surface of the piezoelectric element and the flow path to isolate the flow path;
a regulating portion disposed on a second surface of the piezoelectric element opposite to the first surface and regulating thickness vibration of the piezoelectric element in a direction opposite to the first surface;
A liquid ejecting device comprising: In the liquid ejecting device according to claim 2,
The driving frequency of the piezoelectric element is 100 kHz or higher.
A liquid injection device characterized by: 3. The liquid ejecting device according to claim 1,
the restricting portion is arranged to cover the entire second surface of the piezoelectric element;
A liquid injection device characterized by: The liquid ejecting device according to any one of claims 1 to 3,
the thickness of the diaphragm is thinner than the thickness of the piezoelectric element;
A liquid injection device characterized by: In the liquid ejecting device according to claim 4,
The diaphragm has a thickness of 1 mm or less,
A liquid injection device characterized by: 6. The liquid ejecting device according to claim 4,
The piezoelectric element has a thickness of 1 mm or less.
A liquid injection device characterized by: The liquid ejecting device according to any one of claims 1 to 6,
At least part of the length of the piezoelectric element in a plane perpendicular to the thickness direction is at least 5 times the thickness of the piezoelectric element.
A liquid injection device characterized by: The liquid ejecting device according to any one of claims 1 to 7,
A filling layer is present between the restricting portion and the second surface of the piezoelectric element,
A liquid injection device characterized by: The liquid ejecting device according to claim 8,
the regulation part is formed of a metal material or a ceramic material,
The filling layer is formed of a resin material having a lower bending rigidity than the material of the restricting portion,
A liquid injection device characterized by: 10. The liquid ejecting device according to claim 8,
The restricting portion has a through-hole leading from the back surface on the filling layer side to the front surface,
A liquid injection device characterized by: The liquid ejecting device according to any one of claims 1 to 10,
A control unit that controls the operation of the pressure unit and the piezoelectric element,
The distance from the continuous flow until the liquid ejected from the nozzle splits into droplets under the control of the control unit is 10 mm or less.
A liquid injection device characterized by:

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